The present invention relates generally to sliders for use in magnetic storage drives. In particular, this invention relates to methods and apparatus for finishing a disc drive slider that include lapping a surface of a disc drive slider.
During the fabrication of magnetic heads for use in magnetic data storage applications, an array of transducers and auxiliary circuits are fabricated on a common substrate in a deposition of metallic and non-metallic layers. The array is then cut up into smaller bars, with each bar including a row of multiple read/write heads. The bars are then lapped to adjust an average stripe height (SH) of magnetoresistive (MR) transducers in the bar, the average throat height (TH) of inductive transducer in the bar, or both. The auxiliary circuits in the bars are electrical lap guides (ELGs) that sense the progress of the lapping process. Each electrical lap guide has an electrical resistance that increases as material is removed by lapping. Lapping is stopped automatically when the average stripe height and/or average throat height are within acceptable limits. After the lapping process is complete, the bars are cut up into individual read/write heads or sliders using diamond saws.
The process of lapping a solid bar has a limited ability to adjust only the average stripe height or average throat height for all the sliders formed in the bar. There are remaining undesired variations in individual stripe height or throat height among the sliders in a bar.
As higher recording densities are being introduced, there is a need for better control than this average control, particularly in the case of stripe height. It is, however, inconvenient and expensive to handle individual sliders in a lapping operation because of their small size.
A process and apparatus are needed that can handle bars of substrate with multiple sliders in each bar, while controlling lapping to individually or independently control stripe height for each slider.
Disclosed is a process and apparatus for finishing a disc drive slider. The slider is part of a substrate bar having multiple unfinished sliders formed in it. An etch process is used to etch stress-isolating trenches in the substrate aligned between the sliders and to form webs joining the sliders together. The apparatus includes a pressure generator that applies multiple pressures to the back surface of one individual slider while the front surface of the one individual slider contacts a lapping surface to form a finished front surface of the slider.
After the sliders are finished by lapping, the webs are removed to separate the sliders. The webs flexibly hold the multiple sliders together in a fixture during the lapping process while allowing the individual sliders to move independently. The pressures applied to each individual slider can be independently controlled, allowing for improved control of the stripe height (SH), the throat height (TH) or both of each sldier. The etching process avoids damage from the use of diamond saws.